The Microchip PIC18F26Q43-I/STX is an 8-bit PIC MCU from the PIC® XLP™ 18F family, clocked at 64 MHz with 64KB of Flash program memory, 4K x 8 RAM, and 1K x 8 EEPROM. The XLP (eXtreme Low Power) designation means it's engineered for battery-powered and energy-harvesting applications where every microamp matters. It runs from a 1.8V to 5.5V supply, so it can hang directly off a Li-ion cell or a 3.3V regulated rail without a secondary regulator. The 28-VFQFN package with exposed pad (28-VQFN 4x4mm) is a compact footprint for space-constrained boards. Twenty-five I/O lines are available, which is a lot of GPIO for a 28-pin package — the trade-off is that several functions share pins with the analog front-end, so the pin-mux needs careful planning early in the layout.
Analog integration: 24-channel 12-bit ADC and 8-bit DAC
This part packs a 24-channel 12-bit ADC and a single 8-bit DAC, which is unusual for an 8-bit MCU in this pin count. The 12-bit ADC gives you 4096 counts of resolution — enough for a 0-10V sensor scaled through a divider without losing the bottom end. The 8-bit DAC can generate a reference voltage or an analog setpoint, saving an external DAC or a PWM-plus-filter stage.
Connectivity and industrial temperature range
On the communications side, the PIC18F26Q43 supports I²C, LINbus, SPI, and UART/USART.
For the BOM planner, that means no imminent obsolescence risk and no forced redesign for the next several years.